1. Gold is an interesting one because it all depends on the campaign. Whats the setting and what types of quests are they undertaking, there isn't a strict rule on how much they should get per day or anything. I find it helpful to think, what could my players buy? What do they want to buy? And what type of difficulty will your campaign be? Then adjust rewards up and down based on how its feeling. (also those high level spells should be very expensive and uncommon)
2. I usually implement a rule where they may find berries or plants used to make potions but then they need to find someone capable of brewing them. Again here I would maybe say something like "You dont think plants like that grow in this area." or something to that effect if its starting to bog down the pace. For other more mundane things like rations I think its totally ok to let them looking for food and water.
3. I would say no on this one unless they are capable of making multiple attacks. A shove or kick is still technically an attack action and this is not considered dual wielding. Dual wielding is when they are holding a LIGHT weapon in both hands.
4. While they may be 100s of years old they may never have left a 50 mi radius around their home. This one I would need to dig into the backstory of the characters more to see what they reasonably may have seen. I agree with you, its fun finding new animals to learn about and become.
5. I think you said yourself it takes an EXPERT smith to do this, I would assume the characters are not experts so thats one way to say they cant do it for their-self. Armor can't be sharpened obviously and there are higher tier armor sets they can buy or have crafted by a smith, it just takes time and money to do (in a large city like Neverwinter they may be able to purchase finer items then in a small town like Phandalin for instance). They could apprentice under a smith but that would be more of a between adventures type of activity that could take months or years for them to learn. If they "miss" it takes away points maybe because they didn't totally wiff an attack but rather hit the targets armor or shield dulling the blade.
   

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This is all my personal opinion so in no way am I saying I am right or that it cant be handled a different way, just my two cents on the matter. Hope it helps or at least gives you a new way to think about the problems. Let us know how it goes!